Etiology of diabetic impotence

Autologous Immune Cell-Based Regenerative Therapies to Treat Vasculogenic Erectile Dysfunction: Is the Immuno-Centric Revolution Ready for the Prime Time?

About 35% of patients affected by erectile dysfunction (ED) do not respond to oral phosphodiesterase-5 inhibitors (PDE5i) and more severe vasculogenic refractory ED affects diabetic patients. Innovative approaches, such as regenerative therapies, including stem cell therapy (SCT) and platelet-rich plasma (PRP), are currently under investigation. Recent data point out that the regenerative capacity of stem cells is strongly influenced by local immune responses, with macrophages playing a pivotal role in the injury response and as a coordinator of tissue regeneration, suggesting that control of the immune response could be an appealing approach in regenerative medicine. A new generation of autologous cell therapy based on immune cells instead of stem cells, which could change regenerative medicine for good, is discussed. Increasing safety and efficacy data are coming from clinical trials using peripheral blood mononuclear cells to treat no-option critical limb ischemia and diabetic foot. In this review, ongoing phase 1/phase 2 stem cell clinical trials are discussed. In addition, we examine the mechanism of action and rationale, as well as propose a new generation of regenerative therapies, evolving from typical stem cell or growth factor to immune cell-based medicine, based on autologous peripheral blood mononuclear cells (PBMNC) concentrates for the treatment of ED.

Anatomy, Pathophysiology, Molecular Mechanisms, and Clinical Management of Erectile Dysfunction in Patients Affected by Coronary Artery Disease: A Review

Erectile dysfunction (ED) has been defined as the inability to attain or maintain penile erection sufficient for successful sexual intercourse. ED carries a notable influence on life quality, with significant implications for family and social relationships. Because atherosclerosis of penile arteries represents one of the most frequent ED causes, patients presenting with it should always be investigated for potential coexistent coronary or peripheral disease. Up to 75% of ED patients have a stenosis of the iliac-pudendal-penile arteries, supplying the male genital organ’s perfusion. Recently, pathophysiology and molecular basis of male erection have been elucidated, giving the ground to pharmacological and mechanical revascularization treatment of this condition. This review will focus on the normal anatomy and physiology of erection, the pathophysiology of ED, the relation between ED and cardiovascular diseases, and, lastly, on the molecular basis of erectile dysfunction.

Endovascular therapy for erectile dysfunction: current knowledge and future perspectives

Erectile dysfunction (ED) is defined as the inability to attain or maintain penile erection sufficient for successful sexual intercourse. ED carries a notable influence on quality of life, with significant implications for family and social relationships. Because atherosclerosis of penile arteries represents one of the most frequent causes of ED, patients presenting with it should always be investigated for potential coexistent coronary or peripheral disease. Up to 75% of patients with ED have a stenosis of the iliac-pudendal-penile arteries, supplying perfusion of the male genital organ. Recently the potential treatment of this pathological condition by percutaneous approaches has emerged with good angiographic results and with a significant improvement in symptoms and quality of life. This review will focus on the normal anatomy and physiology of erection, the pathophysiology of ED, the relation between ED and cardiovascular diseases and, lastly, on new treatment modalities aimed at restoration of normal erectile function.

Frequency, severity, and risk factors related to sexual dysfunction in Chinese women with T2D

BACKGROUND

The aim of the present study was to assess the frequency and severity of female sexual dysfunction (FSD) in those with T2D (T2D) compared with non-diabetic controls. In addition, risk factors for FSD were analyzed.

METHODS

Sexual dysfunction, measured using the Female Sexual Function Index (FSFI), was evaluated using a questionnaire in 184 women with T2D and 146 non-diabetic controls at three study sites in China. In the T2D group, FSD was examined by education level, correlations between FSD and other variables were analyzed, and risk factors were studied.

RESULTS

The frequency of FSD in the T2D group was 75.0%, much higher than in the control group (56.2%; P = 0.001). The severity of FSD in the T2D group was 17.84 ± 8.47 (mean ± SD), significantly lower than in the control group (21.14 ± 8.08; P = 0.001). In patients with T2D, being older (P = 0.001), taking oral antidiabetic medications (P = 0.013), and having diabetic neuropathy (P = 0.036) were risk factors for FSD.

CONCLUSIONS

The rate of FSD is high in China and, as seen in the literature, more severe in diabetics than non-diabetics. Being older, taking oral antidiabetic medications, and diabetic neuropathy are risk factors for FSD.

Prevalence of late-onset hypogonadism in men with type 2 diabetes mellitus

Late-onset hypogonadism (LOH) or age-associated testosterone deficiency syndrome is defined as a clinical and biochemical syndrome associated with advancing age and characterised by symptoms and a deficiency in serum testosterone levels. This condition may result in significant detriment in the quality of life and adversely affect the function of multiple organ systems. It has been suggested that sex steroid hormones may play a causal role in the development of insulin resistance and type II diabetes. This comparative study was aimed at determining the prevalence of LOH in diabetic men with erectile dysfunction and investigating the effect of testosterone replacement therapy on erectile function and on glycaemic control.

Men's sexual health and the metabolic syndrome

The aim of this article is to provide an overview of the current literature on the impact of the metabolic syndrome on male sexual health and current developments in the management of sexually dysfunctional men with a metabolic syndrome. The increasing prevalence across the world of the metabolic syndrome-a cluster of cardiovascular disease risk factors-causes the metabolic syndrome to be considered the most important threat to male sexual health of the 21st century. It has been shown to have a negative impact on male sexual function through its relationship with cardiovascular disease risk, its association with hypogonadism, and associated psychosocial factors. Besides established pharmacological and hormonal interventions, lifestyle modification programs are considered important therapeutic tools.

Prevalence of erectile dysfunction among Chinese men with type 2 diabetes mellitus

The aims of this study were to investigate the prevalence of ED in Chinese men with type 2 diabetes mellitus, and evaluate the efficacy and safety of sildenafil citrate in these patients. Patients from 42 outpatient diabetes clinics with type 2 diabetes mellitus and ED as defined by the International Index of Erectile Function (IIEF)-5 were studied. Participants with ED received three doses (100 mg each) of sildenafil citrate for use over 3 months. Efficacy of sildenafil citrate was assessed using the IIEF-5 and the Global Efficacy Questionnaire (GEQ). Adverse events were recorded by patients in a daily diary. A total of 5477 participants were evaluated, and 75.2% had ED. Age, duration of diabetes and glycosylated hemoglobin (HbA(1)c) >6.5% were independently and significantly associated with the presence and degree of ED. Patients who received pharmacotherapy (N=389) reported significant improvements. The rate of erections as determined by the GEQ was also significantly improved following treatment. ED is a common complication in Chinese men with type 2 diabetes mellitus, and certain risk factors are associated with the presence of ED and severity. Sildenafil citrate is a safe and effective treatment for these patients.

Anatomy, physiology, and pathophysiology of erectile dysfunction

INTRODUCTION

Significant scientific advances during the past 3 decades have deepened our understanding of the physiology and pathophysiology of penile erection. A critical evaluation of the current state of knowledge is essential to provide perspective for future research and development of new therapies.

AIM

To develop an evidence-based, state-of-the-art consensus report on the anatomy, physiology, and pathophysiology of erectile dysfunction (ED).

METHODS

Consensus process over a period of 16 months, representing the opinions of 12 experts from seven countries.

MAIN OUTCOME MEASURE

Expert opinion was based on the grading of scientific and evidence-based medical literature, internal committee discussion, public presentation, and debate.

RESULTS

ED occurs from multifaceted, complex mechanisms that can involve disruptions in neural, vascular, and hormonal signaling. Research on central neural regulation of penile erection is progressing rapidly with the identification of key neurotransmitters and the association of neural structures with both spinal and supraspinal pathways that regulate sexual function. In parallel to advances in cardiovascular physiology, the most extensive efforts in the physiology of penile erection have focused on elucidating mechanisms that regulate the functions of the endothelium and vascular smooth muscle of the corpus cavernosum. Major health concerns such as atherosclerosis, hyperlipidemia, hypertension, diabetes, and metabolic syndrome (MetS) have become well integrated into the investigation of ED.

CONCLUSIONS

Despite the efficacy of current therapies, they remain insufficient to address growing patient populations, such as those with diabetes and MetS. In addition, increasing awareness of the adverse side effects of commonly prescribed medications on sexual function provides a rationale for developing new treatment strategies that minimize the likelihood of causing sexual dysfunction. Many basic questions with regard to erectile function remain unanswered and further laboratory and clinical studies are necessary.

Epidemiology of male sexual dysfunction

Male sexual dysfunction includes erectile dysfunction (ED), ejaculation disorders, orgasmic dysfunctions, and disorders of sexual interest/desire. Although current epidemiologic research supports the high prevalence of ED worldwide, incidence data are limited. Furthermore, prevalence data on other male sexual dysfunctions are also limited whereas incidence data are lacking. These epidemiologic data vary widely due to the different definitions used, the method of sampling, and the unknown value of the instruments used to assess sexual dysfunction. Many of the epidemiologic studies are old and associated with poor methodology. Although risk factors for ED are well described, there are almost no data for risk factors in other sexual dysfunctions. The impact of modification of risk factors in sexual dysfunctions is extremely interesting. To provide evidence-based data, there is an urgent need for new, properly designed epidemiological research.

Physiologic measures of sexual function in women: a review

OBJECTIVE

To review and describe physiologic measures of assessing sexual function in women.

DESIGN

Literature review.

SETTING

Studies that use instruments designed to measure female sexual function.

PATIENT(S)

Women participating in studies of female sexual function.

INTERVENTION(S)

Various instruments that measure physiologic features of female sexual function.

MAIN OUTCOME MEASURE(S)

Appraisal of the various instruments, including their advantages and disadvantages.

RESULT(S)

Many unique physiologic methods of evaluating female sexual function have been developed during the past four decades. Each method has its benefits and limitations.

CONCLUSION(S)

Many physiologic methods exist, but most are not well-validated. In addition there has been an inability to correlate most physiologic measures with subjective measures of sexual arousal. Furthermore, given the complex nature of the sexual response in women, physiologic measures should be considered in context of other data, including the history, physical examination, and validated questionnaires. Nonetheless, the existence of appropriate physiologic measures is vital to our understanding of female sexual function and dysfunction.

Gene transfer of vasoactive intestinal polypeptide into the penis improves erectile response in the diabetic rat

OBJECTIVES

To determine the feasibility of transfecting penile corpora cavernosa with pcDNA3/vasoactive intestinal polypeptide (VIP) cDNA, which encodes for VIP in streptozotocin (STZ)-diabetic rats, to clarify whether transfection of VIP cDNA into the cavernosum affects the physiological response to cavernosal nerve stimulation, and whether this process would affect other organs in the diabetic rat model in vivo.

MATERIALS AND METHODS

pcDNA3/VIP cDNA was injected into the corpus cavernosum of STZ-induced diabetic Sprague-Dawley rats. The intracavernosal pressure (ICP) and response to electrical stimulation of the cavernosal nerve (15 Hz, 1.5 ms, 20 V, 1 min) were measured in subsamples of rats at 1, 3, 7 and 14 days after injection; after measuring the ICP the animals were killed, and penile, hepatic, renal artery and abdominal aorta tissue samples were frozen in liquid nitrogen and stored at -80 degrees C. The gene expression of VIP in all samples, assessed as the expression of VIP mRNA, was estimated using a semiquantitative reverse-transcription polymerase chain reaction.

RESULTS

The mean amplitude of ICP and expression of VIP mRNA in the cavernosa of the VIP-treated rats was greater at 1, 3, 7 and 14 days after injection (P < 0.05) than in the control animals. There were no changes in the expression of VIP mRNA in hepatic, renal and abdominal aorta samples after injection (P > 0.05).

CONCLUSIONS

VIP cDNA is easily incorporated into corpus cavernosum, and the expression is sustained for > or = 2 weeks in the penis in vivo. The transfer of VIP is capable of altering the physiologically relevant erectile response, as measured by an increase in the ICP after stimulating the cavernosal nerve. The intracorporal micro-injection of pcDNA3/VIP cDNA had little effect on the expression of VIP mRNA in other important organs.

Nocturnal electrobioimpedance volumetric assessment in diabetic men with erectile dysfunction before and after tadalafil intake

Nocturnal electrobioimpedance volumetric assessment (NEVA) is a procedure that can measure penile volume changes together with the number and duration of nocturnal erectile events. This study was conducted to evaluate the different NEVA patterns in diabetic patients with erectile dysfunction (ED), and demonstrate the extent to which tadalafil may affect the characteristics of nocturnal penile erections in these patients. Therefore, 38 patients with noninsulin-dependent diabetes and ED participated in this study. They were assessed with history intake including evaluation by the abridged five-item version of International Index of Erectile Function, clinical and psychiatric assessment and NEVA for three consecutive nights where placebo was given on the second night and tadalafil on the third night. In all, 14 potent males were taken as a control group. Data were analyzed using t-test. Results showed normal patterns in only six (16%) patients (central organic group), while abnormal patterns were observed in the remaining 32 (84%) patients (peripheral organic group). These abnormal patterns showed significant decrease in both the number (P=0.0001) and duration (P=0.03) of erectile events compared to those of controls. The percentage of penile blood volume change over baseline also decreased significantly (P=0.0002) relative to controls. Veno-occlusive dysfunction was the main pathology (23 patients, 72%) as suggested by NEVA. Tadalafil did not significantly change basal nocturnal penile tumescence results in either the central organic or control groups, but it did so significantly in the peripheral organic group (P=0.02 for duration change and P=0.01 for % blood volume change). In conclusion, NEVA may suggest some evidence about the pathophysiology of an underlying vasculogenic cause, thus directing towards the next specific step needed for a precise diagnosis. Tadalafil improves nocturnal erections in diabetic patients with peripheral but not central organic impotence.

Morphologic findings and blood flow parameters of penile vasculature in patients with erectile dysfunction

The objective was to study the risk factors in patients with erectile dysfunction in correlation with ultrasound findings of penile vasculature. Patients with erectile dysfunction were classified in four groups according to their risk factors. Group A (37 pts) who were heavy smokers, group B (40 pts) who suffered from diabetes mellitus, group C (30 pts) who suffered from hyperlipidemia and group D (40 pts) with no risk factors. The peak systolic velocity (PSV) was measured after the intracavernous injection of 10 mg alprostadile. Normal values were PSV>35 cm/s and endiastolic venous velocity<4 cm/s. It was found that the mean PSV in group A was 22.2+/-2.25 cm/s without venous leakage, in group B the mean PSV was 24.6+/-1.29 cm/s but there was a significant venous leakage (mean end-diastolic velocity 6.2+/-1.37 cm/s). Patients with hyperlipidemia (group C) had a mean PSV of 26.2+/-1.74 cm/s and insignificant venous leakage and patients in group D had a normal vascular profile. Patients with erectile dysfunction who are heavy smokers are predisposed to have penile arterial insufficiency, while diabetics have both arterial insufficiency and venous leakage.

Erectile dysfunction in hemodialysis patients with diabetes mellitus: Association with age and hemoglobin A1c levels

AIM

Erectile dysfunction (ED) is common in patients with diabetes mellitus (DM) as well as those undergoing hemodialysis (HD). The purpose of this study is to investigate the frequency and severity of ED in HD patients with DM and those without DM. In addition, we examined the relationship between erectile function and several risk factors, including presence of DM and hemoglobin A1c levels in HD patients.

METHODS

This study involved 180 patients on HD, including 66 HD patients with DM (DM-HD) and 114 patients without DM (non-DM-HD). We evaluated erectile function using an abridged five-item version of the international index of erectile function (IIEF-5). Logistic regression analysis was used to investigate the relationship between presence of ED and several risk factors.

RESULTS

The total score of IIEF-5 in DM-HD patients (9.5 +/- 4.2) was significantly lower than in non-DM-HD patients (13.5 +/- 5.7). The prevalence of severe ED was 42.4% and 18.4% in DM-HD patients and non-DM-HD patients, respectively. Age, cardiovascular disease history, and DM were identified as independent risk factors for the presence of ED. Furthermore, age and elevated hemoglobin A1c levels were identified as independent risk factors for the presence of severe ED.

CONCLUSION

DM-HD patients are more likely to have ED, and particularly severe forms of ED, than non-DM-HD patients. DM and elevated hemoglobin A1c levels were associated with the presence of ED or severe ED, respectively. Aging was identified as an independent factor in both ED and severe ED.

New Treatment Options for Erectile Dysfunction in Patients with Diabetes Mellitus

Erection is a neurovascular event that involves spinal and supra spinal pathways. The final common pathway involves the release of nitric oxide (NO) from both endothelial cells and neurons, which acts as a vasodilator causing penile engorgement and erection. NO is degraded by the enzyme phosphodiesterase (PDE) type 5 in the penis. Erectile dysfunction (ED), defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance, results when the neurovascular pathway is interrupted by medical conditions or drugs. A 15-item self-administered questionnaire, the International Index of Erectile Function (IIEF), is one of the most useful tools to evaluate erectile function (EF) in clinical trials, although of much less use in routine clinical practice. The MMAS (Massachusetts Male Aging Study) was the first major epidemiological investigation to study the prevalence of ED. The study found that ED was three times more common in patients with diabetes mellitus. The aetiopathogenesis of ED in diabetes is multifactorial, with vascular and neural factors being equally implicated. Hyperglycaemia is believed to give rise to biochemical perturbations that lead to these microvascular changes. In the MMAS, ED in diabetes was strongly correlated with glycaemic control, duration of disease and diabetic complications. The incidence increased with increasing age, duration of diabetes and deteriorating metabolic control, and was higher in individuals with type 2 diabetes than those with type 1.ED in men with diabetes often affects their quality of life and, as patients are often reluctant to come forward with their symptoms, a carefully taken history is one of the most useful approaches in identifying affected individuals. The PDE inhibitors have revolutionised the management of ED and oral drug therapy is currently first-line therapy for the condition. These agents act by potentiating the action of intracavernosal NO, thereby leading to a more sustained erection. Sildenafil was the first PDE5 inhibitor to undergo evaluation and has been studied extensively. More recently two other agents, vardenafil and tadalafil, have been introduced. All the drugs have been shown to be effective across a wide range of aetiologies of ED, including diabetes. The drugs have been shown to improve EF domain scores, penetration and maintenance of erection, resulting in more successful intercourse. Their effects are greater at higher doses. Sildenafil and vardenafil are shorter-acting agents, while tadalafil has a longer half-life allowing the user more flexibility in sexual activity. Common adverse effects include headache, nasal congestion and dyspepsia, all actions related to inhibition of PDE5. The drugs are generally well tolerated and withdrawal from the clinical studies as a result of drug-related adverse effects were rare. The use of PDE5 inhibitors in the presence of oral nitrates is absolutely contraindicated. The clinical studies to date have not evaluated the use of one drug in the case of treatment failure with another agent. Sublingual apomorphine, which stimulates central neurogenic pathways, is a new agent and may be a suitable alternative in those patients in whom PDE5 inhibitors are ineffective or contraindicated. In clinical trials, all IIEF domains except sexual desire were found to have improved after apomorphine. The median times to erection in these studies were 18.9 and 18.8 minutes for the 2 and 3mg doses, respectively. Intraurethral and intracavernosal alprostadil may be a useful alternative when oral drug therapy is ineffective or contraindicated. The management of ED in the diabetic patient may often involve a multidisciplinary approach where psychosexual counselling and specialist urologist advice is required in addition to the skills and expertise of the diabetologist. Finally, the introduction of the new oral agents have completely revolutionised the management of ED and allowed more individuals to come forward for treatment.

Erectile dysfunction: etiology and treatment in young and old patients

This study shows that endocrine and vascular etiologies of erectile dysfunction are more common in the older age group, whereas depression and marital discord are more common in the younger age group. There is considerable overlap between various factors pointing to the multifactorial nature of erectile dysfunction. Review of the treatment option chosen reveals that the invasive modalities were least common as compared with the popular vacuum tumescence device (although cumbersome) and testosterone replacement. Persons with low testosterone have an improved efficacy of sildenafil when hypogonadism is treated. Sildenafil with its ease of administration and high efficacy seems to be the logical first choice for most of the patients. If contraindications exist or treatment failures occur, other treatment options should be offered to patients.

Does sexual dysfunction correlate with deterioration of somatic sensory system in diabetic women?

To evaluate genital and extragenital somatic sensory system in diabetic women using biothesiometry and investigate the relation with sexual dysfunction. A total of 30 diabetic women and 20 normal sexually active women as a control group were evaluated with a detailed medical and sexual history including Index of Female Sexual Function (IFSF) questionnaire. Somatic sensory system of all women enrolled to the study was assessed by biothesiometry and threshold sensory values of nine genital sites and 14 extragenital sites were analyzed. The IFSF score in diabetic women was 23.6 while it was 38.3 in the control group (&<0.0005). For each genital as well as extragenital sites, the mean biothesiometric values were significantly higher in diabetics. The sensation of introitus vagina, labium minora and clitoris were found to be the most deteriorated genital sites in diabetic women. The difference between diabetic women with or without female sexual dysfunction (FSD) was not significant for biothesiometric values. Our data indicate that, somatic sensory system is affected by diabetes however sexual dysfunction does not always manifest.

Effects of tadalafil on erectile dysfunction in men with diabetes

OBJECTIVE

To evaluate the efficacy and safety of tadalafil taken as needed before sexual activity by men with diabetes and erectile dysfunction (ED).

RESEARCH DESIGN AND METHODS

Men with type 1 or type 2 diabetes and a minimum 3-month history of ED were randomly allocated to one of three groups: placebo (n = 71), tadalafil 10 mg (n = 73), or tadalafil 20 mg (n = 72) taken up to once daily for 12 weeks. Changes from baseline in mean scores on the erectile function domain of the International Index of Erectile Function (IIEF) and changes from baseline in the proportion of "yes" responses to question 2, "Were you able to penetrate?," and 3, "Were you able to complete intercourse?," of the Sexual Encounter Profile were coprimary outcome measures.

RESULTS

A total of 191 (88%) of 216 patients completed the study. Treatment with tadalafil significantly improved all primary efficacy variables, regardless of baseline HbA(1c) level. Therapy with tadalafil also significantly improved a number of secondary outcome measures, including changes in other IIEF domains, individual IIEF questions, and percentage of positive responses to a global assessment question measuring erection improvement. Treatment with tadalafil did not alter mean HbA(1c) levels. Tadalafil was well tolerated, with headache and dyspepsia being the most frequent adverse events with active treatment.

CONCLUSIONS

Tadalafil therapy significantly enhanced erectile function and was well tolerated by men with diabetes and ED.

Sexual dysfunction in type II diabetic females: a comparative study

Diabetes Mellitus (DM) is considered to play a principle role in the etiopathogenesis of sexual dysfunction both in men and women. The aim of this study is to evaluate sexual function in Type II diabetic women. A total of 72 young diabetic women (mean age: 38.8 years) with no other systemic diseases and 60 age-matched healthy women were enrolled in our study. We sought from them a detailed medical and sexual history and used the Index of Female Sexual function (IFSF) questionnaire (Kaplan et al., 1999). The mean IFSF score of diabetic women was 29.3 +/- 6.4 and was 37.7 +/- 3.5 in normal cases (p < 0.05). Lack of libido was the most common symptom in diabetics and was observed in 77% of the women. Diminished clitoral sensation was observed in 62.5% of the women, 37.5% complained of vaginal dryness and 41.6% had vaginal discomfort. Orgasmic dysfunction was found in 49% of the women. The incidence of all these related symptoms were significantly higher when compared to controls. We concluded that significant percentage of diabetic women that we observed experience sexual dysfunction of varying degrees that diminishes their quality of life.

Impairment of corpus cavernosal smooth muscle relaxation by glycosylated human haemoglobin

OBJECTIVE

To examine the effect of HbA1c, an isoform of glycosylated haemoglobin (GHb, a product of non-enzymatic reactions between elevated blood glucose and haemoglobin), on nitric oxide-mediated corpus cavernosal smooth muscle relaxation, and to categorize the mechanisms involved.

MATERIALS AND METHODS

Corpus cavernosal tissue from Wistar rats (300-350 g body weight) was prepared for the measurement of isometric tension. After equilibration in Krebs solution gassed with 95% O2/5% CO2 at 37 degrees C for 90 min, optimal resting tension was applied. Tissue was precontracted with 1 micromol/L noradrenaline (NAd) and either relaxed with incremental doses of acetylcholine (ACh) or sodium nitroprusside (SNP). After washout, strips were again precontracted with NAd and then incubated with pyrogallol (100 micromol/L), 100 microL of haemoglobin or 100 microL of GHb in the presence of either L-arginine (100 micromol/L), indomethacin (10 micromol/L), allopurinol (100 micromol/L), deferoxamine (100 micromol/L), catalase (600 IU/mL), or superoxide dismutase (SOD) (120 IU/mL) before ACh- or SNP-induced relaxation responses were repeated.

RESULTS

Haemoglobin and GHb significantly impaired the relaxation of rat corpus cavernosum to ACh in a dose-dependent manner. L-arginine reversed the impairment caused by Hb, but not GHb. A donor of superoxide anions, pyrogallol, mimicked this impairment to ACh when added to control strips. Catalase, deferoxamine, indomethacin and allopurinol had no significant effect on the impaired relaxation response to ACh, whilst L-arginine partially reversed it. SOD completely reversed the GHb-induced impaired relaxation; GHb did not alter the relaxation response to SNP.

CONCLUSION

GHb significantly impairs endothelial NO-mediated corpus cavernosal relaxation in the rat, in vitro. This effect is caused partly by the generation of superoxide anions and the extracellular inactivation of NO.

Impaired ascendant central pathways conduction in impotent diabetic subjects

OBJECTIVES

Diabetic impotence is generally due to peripheral neuropathy, but a central pathway impairment has also been suggested. We evaluated somatosensory transmission in a group of impotent diabetic men to assess the role of central nervous system (CNS) involvement.

MATERIALS AND METHODS

Somatosensory evoked potentials (SEPs) of pudendal (pdn) and posterior tibial (ptn) nerves were recorded in 74 patients. Type and duration of diabetes, severity of sexual dysfunction, medium term metabolic control, occurrence of microangiopathic chronic complications and autonomic neuropathy were evaluated.

RESULTS

Our data show an impairment of central conduction times in pdn (25.7%) and ptn (39.2%) greater than peripheral nervous impairment (pdn 12.2%, ptn 8.1%), in impotent diabetic patients without any further major complication. Central nervous conduction delay resulted to be correlated with poor glycemic control. Significant evident autonomic dysfunction was found only in a minority of cases.

CONCLUSION

Our data might suggest that altered conduction along CNS and somatic peripheral neuropathy might develop independently. We confirm the hypothesis of a "central diabetic neuropathy" and suggest that central sensory pathways involvement, not related to peripheral impairment, could play a role in the pathogenesis of erectile dysfunction in diabetic patients.

Prevalence of sexual disorders in a selection-free diabetic population (JEVIN)

There is an extensive literature on sexual disorders among diabetic patients, but a shortage of studies on their prevalence in selection-free populations. In the present trial (JEVIN), 90% of all insulin-treated diabetic patients (IDDM/NIDDM, n = 127/117) aged 16-60 years and living in the city of Jena (100247 inhabitants) were studied. Each subject underwent a structured interview followed by a clinical and laboratory examination. The prevalence of sexual disorders was 32% in IDDM and 46% in NIDDM male patients. Patients with sexual disorders were older (IDDM 47.5 +/- 9.8 vs. 37.7 +/- 11.6, P = 0.0004; NIDDM 53.4 +/- 4.3 vs. 49.5 +/- 8.2 years, P = 0.04) and had longer diabetes duration (IDDM 23.1 +/- 13.8 vs. 13.5 +/- 11.1, P = 0.001; NIDDM 12.4 +/- 7.5 vs. 8.4 +/- 5.8 years, P = 0.03) than patients without sexual disorders. There were no significant differences (P < 0.05) between the groups as regards HbA1c, body-mass index and insulin dose/kg body weight. The prevalence of diabetes long-term complications in men with versus men without sexual disorders (IDDM/NIDDM): retinopathy, 65/53% vs. 50/18% (P = 0.34/0.03); neuropathy, 58/48% vs. 9/34% (P = 0.001/0.47); nephropathy, 65/50% vs. 12/36% (P = 0.001/0.45). In addition, all the patients completed standardized questionnaires according to Bradley et al. and Lewis et al. to assess quality of life and treatment satisfaction, and one question concerning sexual disorders. The quality of life of IDDM patients with sexual disorders was lower than that of patients without sexual disorders (42.2 +/- 11.4 vs. 54.2 +/- 8.5, P = 0.0005), but there were no differences (P < 0.05) in NIDDM patients. In women, the prevalence of sexual disorders was 18/42% in IDDM and NIDDM. Comparing these data with the literature and with reports from healthy controls, mostly there is clearly an underestimation of the prevalence of sexual disorders in diabetic populations. Physicians must make more efforts to detect and treat sexual disorders, which may result in an improvement of patients' quality of life.

The effects of long-term oral administration of L-arginine on the erectile response of rabbits with alloxan-induced diabetes

OBJECTIVE

To investigate the effects of the long-term oral administration of L-arginine on the impaired neurogenic and endothelium-dependent relaxation responses of corpus cavernosum smooth muscle from alloxan-induced diabetic rabbits.

MATERIALS AND METHODS

Thirty-two New Zealand white rabbits were used in four groups of eight each. In group 1, the rabbits received no treatment after the induction of diabetes with alloxan hydrochloride given intravenously; in group 2, L-arginine (1 mg/mL) was administered orally after the induction of diabetes; in group 3, 6 U/day of insulin was injected subcutaneously; group 4 was maintained with no treatment (as litter-mate controls) for 8 weeks. Thereafter, the rabbits were killed by exsanguination and the penis removed en bloc. The reactivity of corpus cavernosum strips from the penis was then assessed in organ chambers.

RESULTS

Relaxation and contraction responses of corpus cavernosum strips to sodium nitroprusside and potassium chloride, respectively, were similar in all groups. Relaxation responses of corpus cavernosum strips elicited by electrical field stimulation and carbachol from rabbits in group 1 were less than in controls; the responses to carbachol were not significantly impaired in group 2 and 3, whereas responses to electrical field stimulation were impaired in both groups when compared with the control group.

CONCLUSION

The impairment of endothelium-dependent and nerve-mediated relaxation by diabetes appears to involve an alteration in nitric oxide/cyclic GMP pathway. Administration of oral L-arginine increased endothelium-dependent relaxation, probably through activating nitric oxide synthase. Additionally, decreasing elevated blood glucose concentration and advanced glycosylation products by insulin treatment protected endothelium-dependent relaxation, whereas neither L-arginine nor insulin treatment restored impaired neurogenic relaxation.

Development of vascular complications in diabetes

Chronic complications of diabetes are dominated by disorders of the vascular system. They are a much larger burden on both diabetic patients and overall medical costs than diabetes itself. Large vessel problems are far more frequent than microvascular disorders. Loss of arterial elasticity alters arterial flow patterns and increases microcirculatory peak flow rates. Hyperglycemia may directly disrupt elastin formation. Diabetic leg artery disease may be generated by nerve damage, reversing this interactive contribution sequence. The major anatomic feature of microangiopathy in long-term diabetes is an unevenly distributed thickening of the intima of smaller arterioles. The thickening is primarily due to accumulation of type IV (basement membrane) collagen. Arterioles change local vessel diameter to adjust blood distribution to meet current needs. The thickening compromises the maximum local blood flow that may be achieved by this means. Compromise of maximal arteriolar dilatation does not disrupt exercising muscle but in the kidney, retina, and possibly in nerve, local circumstances can generate serious damage. Each of these system's responses has unique features that mediate its vulnerability, but all these organs show arteriolar hyalinization. The increased arteriolar accumulation of type IV collagen appears to be a response to the tangential force generated by flow over local endothelial cells. An increase in peak arteriolar wall force is mediated by a diabetes-specific doubling of erythrocyte membrane curvature change resistance. Red cell aggregation rate determines the rate of damage. The same nonspecific burden may also predispose to heart disease and stroke. Intensive metabolic control improves red cell deformability and protects against arteriolar damage. Therapies that address the rheologic problem more directly may add to the effectiveness of good diabetes control in the future.

Erectile dysfunction in diabetic men: the neurological factor revisited

In the literature the importance of the neurological factor in the etiology of erectile dysfunction in patients with diabetes mellitus is subject to debate. We report on the findings of neurophysiological investigations in 27 impotent and 30 potent diabetic patients, as well as 102 impotent nondiabetic patients. Additionally, hormonal and vascular evaluations were done. The neurophysiological evaluations consisted of assessment of somatic as well as autonomic sensory nerves, by measuring the latencies of somatosensory evoked potentials of the posterior tibial and pudendal nerves, and of the bulbocavernosus and urethro-anal reflexes. The results show a higher incidence of more severe peripheral and autonomic sensory neuropathy in impotent diabetic men. Also, a preponderance of abnormal intracavernous pharmacological tests, suggesting vasculogenic impotence, was found in impotent diabetic patients. No important endocrinological differences were found among the 3 groups under investigation. Significant differences occurred for plasma glucose and glycosylated hemoglobin. We conclude that diabetic urogenital sensory neuropathy has a crucial role in the etiology of diabetic impotence. Angiopathy seems to be of secondary importance. The results show that poor diabetes regulation is associated with diabetic impotence.

Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study

We provide current, normative data on the prevalence of impotence, and its physiological and psychosocial correlates in a general population using results from the Massachusetts Male Aging Study. The Massachusetts Male Aging Study was a community based, random sample observational survey of noninstitutionalized men 40 to 70 years old conducted from 1987 to 1989 in cities and towns near Boston, Massachusetts. Blood samples, physiological measures, socio-demographic variables, psychological indexes, and information on health status, medications, smoking and lifestyle were collected by trained interviewers in the subject's home. A self-administered sexual activity questionnaire was used to characterize erectile potency. The combined prevalence of minimal, moderate and complete impotence was 52%. The prevalence of complete impotence tripled from 5 to 15% between subject ages 40 and 70 years. Subject age was the variable most strongly associated with impotence. After adjustment for age, a higher probability of impotence was directly correlated with heart disease, hypertension, diabetes, associated medications, and indexes of anger and depression, and inversely correlated with serum dehydroepiandrosterone, high density lipoprotein cholesterol and an index of dominant personality. Cigarette smoking was associated with a greater probability of complete impotence in men with heart disease and hypertension. We conclude that impotence is a major health concern in light of the high prevalence, is strongly associated with age, has multiple determinants, including some risk factors for vascular disease, and may be due partly to modifiable para-aging phenomena.

Erectile function and penile blood pressure in diabetes mellitus

Thirty-seven diabetic men selected to exclude the confounding effects of other medical illnesses and nondiabetic medications and 53 healthy controls underwent extensive psychosexual and medical evaluations and penile blood pressure assessments by ultrasonic Doppler measurement and mercury strain-gauge plethysmography. There was a significant negative correlation between age and the penile-brachial index (PBI) in the diabetic but not in the control group. The impotent diabetic group had significantly lower PBI than nondysfunctional diabetic and healthy control subjects. Diabetic type, complications, and adequacy of metabolic control were not statistically related to PBI. Although the PBI may not have diagnostic utility for individual patients, it may provide a valuable noninvasive physiologic measure of penile vascular changes in studies on the aged and the medically ill. The processes that mediate the interaction of diabetes and aging on penile blood pressure and erectile capacity deserve further investigation.

Pathophysiology of erectile dysfunction

During the past decade, our knowledge of the hemodynamics, functional anatomy, neurophysiology, and neuropharmacology of erectile function has evolved substantially. The change of smooth muscle tone has emerged as a key factor in erection and detumescence. However, future studies are needed to elucidate the cellular and molecular basis of erectile physiology. With insight into normal physiology we will understand the pathologic process and be able to treat it.

Evaluation of erectile dysfunction by dynamic infusion cavernosometry and cavernosography (DICC). Multi-institutional study

In a cooperative, private practice, multi-institutional impotence study, dynamic infusion cavernosometry and cavernosography (DICC) was performed on 743 patients to make an accurate diagnosis and/or identify candidates for penile revascularization. Maximum equilibrium intracorporeal pressure achieved following papaverine and phentolamine injection (Phase I) averaged 29.42 +/- 0.76 mm Hg, approximately one third of normal erection pressure. Corporeal pressure fall from 150 mm Hg over thirty seconds (cavernosometry) averaged 82.38 +/- 1.33 mm Hg (Phase II). The gradient between systolic and cavernosal artery pressure averaged 42.84 +/- 1.12 mm Hg on the right and 43.33 +/- 1.13 mm Hg on the left (Phase III). Cavernosography at 90 mm Hg erection pressure was performed in Phase IV. Of the 124 patients from one center who were reviewed in greater detail, pure cavernosal artery insufficiency (CAI) was found in 25 (20.2%), corporeal veno-occlusive dysfunction (CVOD) in 26 (21.0%), and 73 patients (58.9%) demonstrated combined CAI and CVOD. Diabetics (n = 69) achieved lower equilibrium intracorporeal pressures than nondiabetics, had similar CVOD, and worse CAI. Smokers (n = 365) and patients with Peyronie's disease (n = 32) had erectile dysfunction similar to those without these conditions. Patients impotent after trauma (n = 124) were younger, achieved higher intracorporeal pressures, and showed better corporeal veno-occlusive function than those without trauma. Complications of DICC were minimal and infrequent. After DICC, 169 patients underwent internal pudendal arteriography, 105 had arterial bypass surgery with or without penile venous ligation procedures, and 45 had venous surgery alone. Dynamic infusion cavernosometry and cavernosography is a useful erectile function study to evaluate impotence and can be performed easily in a private practice setting.

Male sexual impotence in diabetes mellitus: vasculogenic versus neurogenic factors

In an attempt to understand better the role of vascular and neurogenic alterations in the pathophysiology of diabetic impotence, 29 impotent male patients with diabetes mellitus (DM) were investigated by means of doppler ultrasound examination (DUE) of penile arteries, sacral evoked responses (SERs), peripheral nerve conduction studies, and, in most cases, nocturnal penile tumescence monitoring (NPTM). Fourteen patients showed isolated alterations of penile vascular supply, four isolated alterations of penile segmental innervation, and seven combined vasculogenic and neurogenic abnormalities; finally, in four patients, DUE, SERs, and NPTM were normal. One patient, in spite of the presence of marked vasculogenic and neurogenic alterations, showed nocturnal penile erections. Results confirm that vascular obstruction, more than nerve damage, plays a primary role in the pathophysiology of diabetic erectile failure, and stress the importance of psychogenic factors. The observation that some patients presented marked involvements of both arterial supply and neurological pathways only a few years, or even 1 year, after the diagnosis of the disease, indicates the need of an early screening of the vascular and neurological status, even in asymptomatic patients. Furthermore, all patients with altered SERs had peripheral neuropathy; on the other hand, six patients with peripheral neuropathy had normal SERs. This result stresses the diagnostic importance of the electrophysiologic studies of sacral segmental innervation and indicates further that in a comprehensive diagnostic protocol of diabetic impotence the study of SERs should be performed only in patients with peripheral neuropathy.

Impotence in diabetes: aetiology, implications for treatment and preferred vacuum device

In an assessment of the contributions of autonomic neuropathy and vascular disease to the aetiology of male impotence in diabetes, evidence of autonomic neuropathy was identified in 23/39 (59%) individuals complaining of impotence. Thirteen of 26 men aged < 60 years tested with an intracorporeal injection of papaverine experienced little or no response and seven had tumescence but no rigidity. Radioisotope phallography demonstrated vascular disease in six of these seven, suggesting evidence of a vascular component in 19/26 (73%). Only one patient had non-organic impotence. Overall, evidence of vascular disease alone was demonstrated in 10/26 (38%), vascular disease plus autonomic neuropathy in 9/26 (35%), and autonomic neuropathy alone in 6/26 (23%). Many diabetic men complaining of impotence appear to have a significant vascular component which renders intracorporeal papaverine treatment ineffective. We compared the performance of a vacuum constriction-band (Erecaid) and condom-type (Synergist) device in 10 randomly selected men from this group. The devices, provided in random order for 5 months each, were assessed by questionnaire and interview of both the patient and partner. Two couples defaulted and another could use neither device. Although erectile capacity could be restored in the remainder, subsequent intercourse was only deemed satisfactory to both partners in five couples, who unanimously preferred the constriction-band device. In treatment with vacuum devices the constriction-band type seems to be the device of choice; the condom type should probably be reserved for those unable to use the constriction-band type.

Retrospective review of sexual and marital satisfaction of spinal cord injury and diabetic males post penile injection or implant

This study compares sexual activity and sexual and marital satisfaction in spinal-cord-injured (SCI) and diabetic men who had received either a penile prosthesis or papaverine/phentolamine injections for the treatment of impotence. Questionnaires were used retrospectively to assess changes pre- and post-procedure in 30 SCI and 26 diabetic males. Regardless of whether they received a penile prosthesis or injections, both diabetic and SCI males reported increases in diversity and frequency of sexual activities and satisfaction with sexual activities post-implant/injection. When compared with a normative sample, both diabetic and SCI males were found to have poorer body image post-implant/injection. They also reported more disagreement with their partners but engaged in more activities together.

Neurological risk profile in organic erectile impotence

Thirty men who presented with erectile impotence to the urological department underwent a thorough urological, angiological, and neurological examination with complementary neurophysiological tests of somatosensory and sympathetic and parasympathetic function. Most had vascular and neurological abnormalities. Clinical findings and electrophysiological tests for autonomic dysfunction had the highest yield of abnormal results. Nerve conduction studies and pudendal nerve somatosensory evoked potentials were far less informative. The lack of correlation between vascular and general neurological abnormalities emphasises that patients must be screened for both vascular and neurological dysfunction to prevent unrewarding vascular operation in impotent men.

Development of the male function profile/impotence questionnaire

This paper describes three studies conducted to develop the Male Function Profile/Impotence Questionnaire as well as the psychometric properties of the instrument. The questionnaire is computer scored and, based on an interactional model, differentiates between organogenic and psychogenic causes for erectile dysfunction. Each subject is assigned one of 21 impotence profiles. Additional work-up recommendations are based on a breakdown and narrative describing all medical and psychological factors which bear on the subject's impotence.

Etiologic aspects of impotence in diabetes

An investigation of 37 diabetics with impotence (15) or erectile difficulties (22) is presented. On average two significant abnormalities per patient were found. Ranked in order of incidence, the causes were as follows: 1) Combination of neuropathy and psychosocial factors, 2) combination of neuropathy and vascular disease, 3) peripheral neuropathy only, 4) combination of hormonal imbalance and psychosocial factors, 5) combination of three or more defects, and 6) penile vascular disease or psychosocial problems only, or hormonal imbalance combined with peripheral neuropathy.